/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_cmplx_mult_cmplx_q31.c
*
* Description:	Q31 complex-by-complex multiplication
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @addtogroup CmplxByCmplxMult
 * @{
 */


/**
 * @brief  Q31 complex-by-complex multiplication
 * @param[in]  *pSrcA points to the first input vector
 * @param[in]  *pSrcB points to the second input vector
 * @param[out]  *pDst  points to the output vector
 * @param[in]  numSamples number of complex samples in each vector
 * @return none.
 *
 * <b>Scaling and Overflow Behavior:</b>
 * \par
 * The function implements 1.31 by 1.31 multiplications and finally output is converted into 3.29 format.
 * Input down scaling is not required.
 */

void arm_cmplx_mult_cmplx_q31(
    q31_t* pSrcA,
    q31_t* pSrcB,
    q31_t* pDst,
    uint32_t numSamples)
{
	q31_t a, b, c, d;                              /* Temporary variables to store real and imaginary values */
	uint32_t blkCnt;                               /* loop counters */
	q31_t mul1, mul2, mul3, mul4;
	q31_t out1, out2;

#ifndef ARM_MATH_CM0

	/* Run the below code for Cortex-M4 and Cortex-M3 */

	/* loop Unrolling */
	blkCnt = numSamples >> 2u;

	/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
	 ** a second loop below computes the remaining 1 to 3 samples. */
	while(blkCnt > 0u) {
		/* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
		/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
		a = *pSrcA++;
		b = *pSrcA++;
		c = *pSrcB++;
		d = *pSrcB++;

		mul1 = (q31_t)(((q63_t) a * c) >> 32);
		mul2 = (q31_t)(((q63_t) b * d) >> 32);
		mul3 = (q31_t)(((q63_t) a * d) >> 32);
		mul4 = (q31_t)(((q63_t) b * c) >> 32);

		mul1 = (mul1 >> 1);
		mul2 = (mul2 >> 1);
		mul3 = (mul3 >> 1);
		mul4 = (mul4 >> 1);

		out1 = mul1 - mul2;
		out2 = mul3 + mul4;

		/* store the real result in 3.29 format in the destination buffer. */
		*pDst++ = out1;
		/* store the imag result in 3.29 format in the destination buffer. */
		*pDst++ = out2;

		a = *pSrcA++;
		b = *pSrcA++;
		c = *pSrcB++;
		d = *pSrcB++;

		mul1 = (q31_t)(((q63_t) a * c) >> 32);
		mul2 = (q31_t)(((q63_t) b * d) >> 32);
		mul3 = (q31_t)(((q63_t) a * d) >> 32);
		mul4 = (q31_t)(((q63_t) b * c) >> 32);

		mul1 = (mul1 >> 1);
		mul2 = (mul2 >> 1);
		mul3 = (mul3 >> 1);
		mul4 = (mul4 >> 1);

		out1 = mul1 - mul2;
		out2 = mul3 + mul4;

		/* store the real result in 3.29 format in the destination buffer. */
		*pDst++ = out1;
		/* store the imag result in 3.29 format in the destination buffer. */
		*pDst++ = out2;

		a = *pSrcA++;
		b = *pSrcA++;
		c = *pSrcB++;
		d = *pSrcB++;

		mul1 = (q31_t)(((q63_t) a * c) >> 32);
		mul2 = (q31_t)(((q63_t) b * d) >> 32);
		mul3 = (q31_t)(((q63_t) a * d) >> 32);
		mul4 = (q31_t)(((q63_t) b * c) >> 32);

		mul1 = (mul1 >> 1);
		mul2 = (mul2 >> 1);
		mul3 = (mul3 >> 1);
		mul4 = (mul4 >> 1);

		out1 = mul1 - mul2;
		out2 = mul3 + mul4;

		/* store the real result in 3.29 format in the destination buffer. */
		*pDst++ = out1;
		/* store the imag result in 3.29 format in the destination buffer. */
		*pDst++ = out2;

		a = *pSrcA++;
		b = *pSrcA++;
		c = *pSrcB++;
		d = *pSrcB++;

		mul1 = (q31_t)(((q63_t) a * c) >> 32);
		mul2 = (q31_t)(((q63_t) b * d) >> 32);
		mul3 = (q31_t)(((q63_t) a * d) >> 32);
		mul4 = (q31_t)(((q63_t) b * c) >> 32);

		mul1 = (mul1 >> 1);
		mul2 = (mul2 >> 1);
		mul3 = (mul3 >> 1);
		mul4 = (mul4 >> 1);

		out1 = mul1 - mul2;
		out2 = mul3 + mul4;

		/* store the real result in 3.29 format in the destination buffer. */
		*pDst++ = out1;
		/* store the imag result in 3.29 format in the destination buffer. */
		*pDst++ = out2;

		/* Decrement the blockSize loop counter */
		blkCnt--;
	}

	/* If the blockSize is not a multiple of 4, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = numSamples % 0x4u;

	while(blkCnt > 0u) {
		/* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
		/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
		a = *pSrcA++;
		b = *pSrcA++;
		c = *pSrcB++;
		d = *pSrcB++;

		mul1 = (q31_t)(((q63_t) a * c) >> 32);
		mul2 = (q31_t)(((q63_t) b * d) >> 32);
		mul3 = (q31_t)(((q63_t) a * d) >> 32);
		mul4 = (q31_t)(((q63_t) b * c) >> 32);

		mul1 = (mul1 >> 1);
		mul2 = (mul2 >> 1);
		mul3 = (mul3 >> 1);
		mul4 = (mul4 >> 1);

		out1 = mul1 - mul2;
		out2 = mul3 + mul4;

		/* store the real result in 3.29 format in the destination buffer. */
		*pDst++ = out1;
		/* store the imag result in 3.29 format in the destination buffer. */
		*pDst++ = out2;

		/* Decrement the blockSize loop counter */
		blkCnt--;
	}

#else

	/* Run the below code for Cortex-M0 */

	/* loop Unrolling */
	blkCnt = numSamples >> 1u;

	/* First part of the processing with loop unrolling.  Compute 2 outputs at a time.
	 ** a second loop below computes the remaining 1 sample. */
	while(blkCnt > 0u) {
		/* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
		/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
		a = *pSrcA++;
		b = *pSrcA++;
		c = *pSrcB++;
		d = *pSrcB++;

		mul1 = (q31_t)(((q63_t) a * c) >> 32);
		mul2 = (q31_t)(((q63_t) b * d) >> 32);
		mul3 = (q31_t)(((q63_t) a * d) >> 32);
		mul4 = (q31_t)(((q63_t) b * c) >> 32);

		mul1 = (mul1 >> 1);
		mul2 = (mul2 >> 1);
		mul3 = (mul3 >> 1);
		mul4 = (mul4 >> 1);

		out1 = mul1 - mul2;
		out2 = mul3 + mul4;

		/* store the real result in 3.29 format in the destination buffer. */
		*pDst++ = out1;
		/* store the imag result in 3.29 format in the destination buffer. */
		*pDst++ = out2;

		a = *pSrcA++;
		b = *pSrcA++;
		c = *pSrcB++;
		d = *pSrcB++;

		mul1 = (q31_t)(((q63_t) a * c) >> 32);
		mul2 = (q31_t)(((q63_t) b * d) >> 32);
		mul3 = (q31_t)(((q63_t) a * d) >> 32);
		mul4 = (q31_t)(((q63_t) b * c) >> 32);

		mul1 = (mul1 >> 1);
		mul2 = (mul2 >> 1);
		mul3 = (mul3 >> 1);
		mul4 = (mul4 >> 1);

		out1 = mul1 - mul2;
		out2 = mul3 + mul4;

		/* store the real result in 3.29 format in the destination buffer. */
		*pDst++ = out1;
		/* store the imag result in 3.29 format in the destination buffer. */
		*pDst++ = out2;

		/* Decrement the blockSize loop counter */
		blkCnt--;
	}

	/* If the blockSize is not a multiple of 2, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = numSamples % 0x2u;

	while(blkCnt > 0u) {
		/* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
		/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
		a = *pSrcA++;
		b = *pSrcA++;
		c = *pSrcB++;
		d = *pSrcB++;

		mul1 = (q31_t)(((q63_t) a * c) >> 32);
		mul2 = (q31_t)(((q63_t) b * d) >> 32);
		mul3 = (q31_t)(((q63_t) a * d) >> 32);
		mul4 = (q31_t)(((q63_t) b * c) >> 32);

		mul1 = (mul1 >> 1);
		mul2 = (mul2 >> 1);
		mul3 = (mul3 >> 1);
		mul4 = (mul4 >> 1);

		out1 = mul1 - mul2;
		out2 = mul3 + mul4;

		/* store the real result in 3.29 format in the destination buffer. */
		*pDst++ = out1;
		/* store the imag result in 3.29 format in the destination buffer. */
		*pDst++ = out2;

		/* Decrement the blockSize loop counter */
		blkCnt--;
	}

#endif /* #ifndef ARM_MATH_CM0 */

}

/**
 * @} end of CmplxByCmplxMult group
 */
